1. Field of the Invention
The present invention relates to an apparatus and a method for driving a display panel. More specifically, the present invention relates to an apparatus and method for driving a plasma display panel (PDP), using an adaptive waveform mechanism that efficiently utilizes a pause period, which occurs in realizing automatic power control (APC) operation for controlling power consumption.
2. Discussion of the Related Art
A PDP is a display device that has a plurality of discharge cells in a matrix form. The PDP selectively activates the cells to emit light and reconstitutes input image data.
PDPs have at least one pair of a scan electrode and a sustain electrode. There are electrodes arranged opposing each other in parallel. The PDP has at least one address electrode disposed perpendicular to the scan electrode and the sustain electrodes. An addressing operation is performed by applying a scan pulse voltage to at least one of the scan electrode and the sustain electrode and an address voltage to the address electrode. As a result, a discharge between the scan electrode or the sustain electrode and the address electrode, changes electrical properties at the intersection of those electrodes to be addressed. A sustain operation applies a sustain pulse voltage between the scan electrode and the sustain electrode after the addressing operation, thereby causing a discharge where the electrical properties have changed.
The PDP should be capable of displaying various gray scales, for use as a color display device. It shows such gray scales by dividing a field into a plurality of sub-fields and controlling the sub-fields via time division control.
Among the PDP driving methods currently used, the address display separation (ADS) driving method starts sustain operation after completing the address operation for the entire PDP. Thus, the address operation and the sustain operation is totally separated. The ADS driving method is now adopted by most PDP manufacturers and employed by the present invention.
The PDP has a high power consumption due to its driving mechanism. The APC technique is used to control power consumption according to the load rate (i.e., average signal level or load ratio) of a frame to be displayed. The APC technique is an approach for controlling power consumption by varying the number of sustain pulses according to the load rate of image data.
When using the APC technique for driving the PDP, a pause period occurs in a field during which none of the reset, address, and sustain sequences are activated. The pause period refers to an interval during which no operation is activated in the reset, address, and sustain intervals.
FIG. 1 illustrates pause period distribution of APC levels in the related art. The triangle area (A) represents the pause period in driving the PDP when using the APC technique. According to the related art there is no special processing for the pause interval. The pause interval lasts longer when using a slow APC.
The address delays occurring in the address intervals among the PDP driving sequences may be changed to be longer or shorter according to the charge distribution before discharging the cells of the PDP. One technique is a Slow APC that changes the APC level at intervals of 0.5 seconds, thereby the brightness change of the display cannot be recognized at the APC levels sensed by the human retina and is mostly concentrated in the latter part of the sub-field array. An increased address delay makes the discharge of the discharge cells unstable and increases the possibility of an abnormal addressing operation, thereby making the reset, address, and sustain sequences non-uniform.